WHY DOES THIS COFFEE TASTE DIFFERENT THAN IT DID LAST TIME?

Let’s start with the coffee and figure out how the coffee itself could be different day to day. We already know that coffee stales just a little bit everyday and that if it is already ground, the process happens at a much faster rate. But is it really that fast a process?

Probably not, at least, not so fast that we can tell after just one day.

What we always assume, though, is that the bag or can of coffee is perfectly homogenous, that is, every bean inside is nearly identical. The truth is, that rarely happens.

Sometimes, bad beans make it into the lot. These beans are usually bad from the start—they were picked that way or they processed poorly and were mixed in with good coffee.

While there are many ways of sorting out bad beans (hand picking, screening by size, separating by density, and color sorting) none of them are perfect. Bad beans will always sneak through the system.

Did you know?

A pound (455 g) of medium roasted coffee will be composed of 2,800–4,725 coffee beans (depending on their density).

Sometimes, you can see these beans in a bag of whole bean coffee. They often are discolored (usually lighter) but really junk ones can be all black. Some are broken or have evident insect damage. These beans are more difficult to see and taste in darker roasted coffees, but some can still leave their mark on the cup. Every so often, though, beans that make it past all the sorting and look just fine in the roasted bag still end up tasting a bit off from the rest.

Generally, there aren’t very many of these beans. So, the odds of one getting into any given pot are low. Even if it did make it into a pot, if it were just one bean, it would probably be so diluted as to be unrecognizable. As an extension, a bag of ground beans are likely to be much more homogenous as they’ll be able to mix much better. If you are brewing just one cup at a time, though (an increasingly common practice), a single bean can make an incredibly big difference. So, it might just be the case that one bad bean spoils the whole cup, making today’s cup different than yesterday’s.

Hopefully, though, that doesn’t happen too often, which suggests that differences in how our coffee tastes day to day are due to something in our heads. We are thinking, feeling creatures who use our brains to process everything. Whether it is a translation of the electrical signal received after a sugar molecule interacts with a taste bud or the frustration from the cat leaving a carcass in the hallway, or our brain interpreting the gestalt of the experience of an incredible cup of coffee, it is all dependent upon our psychology and how our brains work. So, we’re not actually crazy; we’re just human. And this means all kinds of explanations exist to explain this inconsistent coffee phenomenon! 

Did you know?